芯片上叉指电极介电电泳的模拟与实验研究

Simulation and Experimental Study of Dielectrophoresis in a Microfluidic Chip with Interdigitated Electrodes

分析了影响常规介电电泳过程中粒子所受介电电泳力的因素和发生正、负向介电电泳的条件。经过合理的简化和假设,建立了一个芯片微通道中常规介电电泳的二维数学模型。数值计算结果给出了微通道中的电势和电场强度分布,并根据场强分布预测了粒子发生正向介电电泳时最容易被吸附的位置。利用微加工工艺,在硼硅酸(Pyrex)玻璃表面沉积了叉指型结构的复合金属电极,并用聚二甲基硅氧烷(PDMS)制作了具有微通道的盖片,两者键合形成芯片。以溶解有聚苯乙烯(polystyrene,PS)粒子的KCl溶液为操作悬浮溶液进行了粒子正向介电电泳实验,实验结果与理论分析具有较好的吻合。

The factors affecting the dielectrophoretic forces of the particles in conventional dielectrphoresis, as well as the conditions for the positive or negative dielectrophoresis were analyzed. A two dimensional mathematical model for the conventional dielectrophoresis in microchannels was developed through proper simplifications and assumptions. The numerical computation illustrates the distribution of electrical potential and electrical field, and predicts the positions where the particles of positive dielectrphoresis occurred are most likely to be adhered. A Pyrex glass/ PDMS microfluidic chip with the interdigitated electrode array on the glass wafer and the microchannel in the PDMS cover was fabricated, and the positive dielectrphoresis experiments of polystyrene beads in KCl solution were carried out. It is found that the experimental result agrees well with the numerical predication.